Autism is a disabling neurological disorder that affects thousands of Americans and encompasses a number of subtypes, with various putative causes and few documented ameliorative treatments. The disorders of the autistic spectrum may be present at birth, or may have later onset, for example, at ages two or three. There are no clear cut biological markers for autism. Diagnosis of the disorder is made by considering the degree to which the child matches the behavioral syndrome, which is characterized by poor communicative abilities, peculiarities in social and cognitive capacities, and maladaptive behavioral patterns.
A number of different treatments for autism have been developed. Many of the treatments, however, address the symptoms of the disease, rather than the causes. For example, therapies ranging from psychoanalysis to psychopharmacology have been employed in the treatment of autism. Although some clinical symptoms may be lessened by these treatments, modest improvement, at best, has been demonstrated in a minor fraction of the cases. Only a small percentage of autistic persons become able to function as self-sufficient adults.
Although much controversy exists about the causes and treatments of autism, a few established biomedical findings have been made. Many individuals with autism experience intestinal difficulties, often including the inability to digest gluten and casein. Abnormalities have also been found in the metabolism of the neurotransmitter serotonin and in various parameters of immune system functions, for example, elevated Measles, Mumps and Rubella (MMR) titers. Prior to the discovery of the present invention, however, no useful links had been made between these biomedical findings, nor had any successful treatments been derived therefrom, as disclosed in various articles incorporated herein by reference..sup.1
 FNT .sup.1 Priven, J. (1997). The biological basis of autism. Current Opinion in Neurobiology, 7, 708-712.
 FNT Rapin, L. & Katzman, R. (1998). Neurobiology of autism. Ann Neurology, 43, 7-14.
Similar to autistic spectrum disorder, many other behavioral, neurological and immunological disorders have been equally difficult to understand and to effectively treat. Such disorders include depression, obsessive-compulsive disorder, Alzheimer's, allergies, anorexia, schizophrenia, as well as other neurological conditions resulting from improper modulation of neurotransmitter levels or improper modulation of immune system functions, as well as behavioral disorders such as ADD (Attention Deficit Disorder) and ADHD (Attention Deficit Hyperactivity Disorder), for example. Accordingly, a need exists for a method and composition for the treatment of autism and other behavioral, neurological and/or immunological disorders.
The hormone secretin is a polypeptide hormone secreted by the mucosa of the duodenum and upper jejunum when acid chyme enters the intestine. The hormone secretin stimulates the pancreatic acinar cells to release bicarbonate and water, which are excreted into the duodenum and change the pH in the gut from acid to alkaline, thereby facilitating the action of digestive enzymes. Secretin is always used and indeed is intended only to be used in diagnostic tests given to patients with gastrointestinal disorders to stimulate the release of pancreatic juices for testing purposes.
Prior to the discovery of the present invention, however, secretin has never before been linked to autistic spectrum disorders, either as a possible cause or treatment, nor has it been used in the treatment of other neurological and/or
 FNT Wing, L. (1997). The autistic spectrum. The Lancet, 350 (dec. 13), 1761-1765. immunological disorders, as herein proposed.